Many parameters such as network and codec delay, packet loss, codec performance affect the user's perception of the quality of service (QoS) of a packet-based telephony call, as compared to an end-to end TDM telephone call.
The Nortel Networks “Meridian” Internet Telephony Gateway Trunk (“Meridian” is a Trade Mark) can measure the latency and packet loss during a telephone call using the Internet Protocol. These factors directly affect the perceived QoS and can be used to generate a measurement of network performance during a call. If the measurement of network performance drops below a predetermined value, the system can be programmed to switch the call from the switched packet network to a conventional analog network, thereby ensuring that the user has an acceptable level of call quality at all times.
However, users do not themselves currently have any way of monitoring the QoS in an objective way. Users can only give subjective reactions that the QoS has improved or declined during a call.
This contrasts to GSM or other mobile communications, in which a single parameter, i.e. the strength of signal from the local base station, provides an accurate guide to the quality of the call, or in the case of two users each on mobile handsets, the quality at each end. Thus, many handsets have a signal strength indicator which allows a user to monitor the signal strength during a call. A method of monitoring QoS for a packet-based telephony call would be attractive to users and would add value to the network or equipment provider who is supplying the QoS information.
It is therefore an object of this invention to provide a method of monitoring quality of in communications over a packet-based network.